user: Question: With a North Melbourne away team, what is the average crowd?
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', '15.11 (101)', 'St Kilda', '17.9 (111)', 'Glenferrie Oval', 19279.0, '29 June 1968']
SQL:

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