user: Question: What is the average crowd size when Fitzroy plays at home?
Columns: ['Home team', 'Home team score', 'Away team', 'Away team score', 'Venue', 'Crowd', 'Date']
Types: ['text', 'text', 'text', 'text', 'text', 'real', 'text']
Sample row: ['St Kilda', '5.18 (48)', 'Melbourne', '10.12 (72)', 'Junction Oval', 30000.0, '25 April 1960']
SQL:

assistant: SELECT AVG("Crowd") FROM "Table" WHERE "Home team" = 'Fitzroy';