user: Question: What is the average crowd for the home team of 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', '4.12 (36)', 'St Kilda', '9.9 (63)', 'MCG', 15826.0, '4 July 1931']
SQL:

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