What is the production code of the episode that was watched by 3.81 million U.S. viewers?
CREATE TABLE table_29054902_1 (
    production_code VARCHAR,
    us_viewers__million_ VARCHAR
)
SELECT production_code FROM table_29054902_1 WHERE us_viewers__million_ = "3.81"
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 production code of the episode that was watched by 3.81 million U.S. viewers? ### Input: CREATE TABLE table_29054902_1 (
    production_code VARCHAR,
    us_viewers__million_ VARCHAR
) ### Response: SELECT production_code FROM table_29054902_1 WHERE us_viewers__million_ = "3.81"