user: Question: What is the sum of all the crowds that watched North Melbourne 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', '7.11 (53)', 'South Melbourne', '10.21 (81)', 'Junction Oval', 15000.0, '14 August 1926']
SQL:

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