What's the post position when the lengths behind is 0?
CREATE TABLE table_76593 (
    "Finish Position" text,
    "Lengths Behind" text,
    "Post Position" real,
    "Horse name" text,
    "Trainer" text,
    "Jockey" text,
    "Owner" text,
    "Post Time Odds" text
)
SELECT AVG("Post Position") FROM table_76593 WHERE "Lengths Behind" = '0'
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's the post position when the lengths behind is 0? ### Input: CREATE TABLE table_76593 (
    "Finish Position" text,
    "Lengths Behind" text,
    "Post Position" real,
    "Horse name" text,
    "Trainer" text,
    "Jockey" text,
    "Owner" text,
    "Post Time Odds" text
) ### Response: SELECT AVG("Post Position") FROM table_76593 WHERE "Lengths Behind" = '0'