user: Question: How many people were in the crowd when the away team was 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: ['Hawthorn', '20.18 (138)', 'South Melbourne', '15.16 (106)', 'Princes Park', 11657.0, '20 June 1981']
SQL:

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