What is the type of the organization with the most research staff?
CREATE TABLE project_staff (
    staff_id number,
    project_id number,
    role_code text,
    date_from time,
    date_to time,
    other_details text
)

CREATE TABLE project_outcomes (
    project_id number,
    outcome_code text,
    outcome_details text
)

CREATE TABLE tasks (
    task_id number,
    project_id number,
    task_details text,
    eg agree objectives text
)

CREATE TABLE projects (
    project_id number,
    organisation_id number,
    project_details text
)

CREATE TABLE document_types (
    document_type_code text,
    document_description text
)

CREATE TABLE organisation_types (
    organisation_type text,
    organisation_type_description text
)

CREATE TABLE organisations (
    organisation_id number,
    organisation_type text,
    organisation_details text
)

CREATE TABLE grants (
    grant_id number,
    organisation_id number,
    grant_amount number,
    grant_start_date time,
    grant_end_date time,
    other_details text
)

CREATE TABLE research_staff (
    staff_id number,
    employer_organisation_id number,
    staff_details text
)

CREATE TABLE research_outcomes (
    outcome_code text,
    outcome_description text
)

CREATE TABLE staff_roles (
    role_code text,
    role_description text
)

CREATE TABLE documents (
    document_id number,
    document_type_code text,
    grant_id number,
    sent_date time,
    response_received_date time,
    other_details text
)
SELECT T1.organisation_type FROM organisations AS T1 JOIN research_staff AS T2 ON T1.organisation_id = T2.employer_organisation_id GROUP BY T1.organisation_type ORDER BY COUNT(*) DESC LIMIT 1
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: What is the type of the organization with the most research staff? ### Input: CREATE TABLE project_staff (
    staff_id number,
    project_id number,
    role_code text,
    date_from time,
    date_to time,
    other_details text
)

CREATE TABLE project_outcomes (
    project_id number,
    outcome_code text,
    outcome_details text
)

CREATE TABLE tasks (
    task_id number,
    project_id number,
    task_details text,
    eg agree objectives text
)

CREATE TABLE projects (
    project_id number,
    organisation_id number,
    project_details text
)

CREATE TABLE document_types (
    document_type_code text,
    document_description text
)

CREATE TABLE organisation_types (
    organisation_type text,
    organisation_type_description text
)

CREATE TABLE organisations (
    organisation_id number,
    organisation_type text,
    organisation_details text
)

CREATE TABLE grants (
    grant_id number,
    organisation_id number,
    grant_amount number,
    grant_start_date time,
    grant_end_date time,
    other_details text
)

CREATE TABLE research_staff (
    staff_id number,
    employer_organisation_id number,
    staff_details text
)

CREATE TABLE research_outcomes (
    outcome_code text,
    outcome_description text
)

CREATE TABLE staff_roles (
    role_code text,
    role_description text
)

CREATE TABLE documents (
    document_id number,
    document_type_code text,
    grant_id number,
    sent_date time,
    response_received_date time,
    other_details text
) ### Response: SELECT T1.organisation_type FROM organisations AS T1 JOIN research_staff AS T2 ON T1.organisation_id = T2.employer_organisation_id GROUP BY T1.organisation_type ORDER BY COUNT(*) DESC LIMIT 1