user: Question: What was the date of the game when North Melbourne was the away team?
Columns: ['Home team', 'Home team score', 'Away team', 'Away team score', 'Venue', 'Crowd', 'Date']
Types: ['text', 'text', 'text', 'text', 'text', 'real', 'text']
Sample row: ['Richmond', '11.17 (83)', 'St Kilda', '16.10 (106)', 'Punt Road Oval', 23000.0, '30 May 1959']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Away team" = 'North Melbourne';