user: Question: What is the average crowd when the home team is North Melbourne?
Columns: ['Home team', 'Home team score', 'Away team', 'Away team score', 'Venue', 'Crowd', 'Date']
Types: ['text', 'text', 'text', 'text', 'text', 'real', 'text']
Sample row: ['Melbourne', '18.16 (124)', 'South Melbourne', '10.13 (73)', 'MCG', 23000.0, '26 July 1941']
SQL:

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