What is the 1st leg when club is a.c. libertas?
CREATE TABLE table_500 (
    "Season" text,
    "Competition" text,
    "Round" text,
    "Club" text,
    "1st leg" text,
    "2nd leg" text,
    "Aggregate" text
)
SELECT "1st leg" FROM table_500 WHERE "Club" = 'A.C. Libertas'
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 1st leg when club is a.c. libertas? ### Input: CREATE TABLE table_500 (
    "Season" text,
    "Competition" text,
    "Round" text,
    "Club" text,
    "1st leg" text,
    "2nd leg" text,
    "Aggregate" text
) ### Response: SELECT "1st leg" FROM table_500 WHERE "Club" = 'A.C. Libertas'