user: Question: When was the game played at the Western Oval venue?
Columns: ['Home team', 'Home team score', 'Away team', 'Away team score', 'Venue', 'Crowd', 'Date']
Types: ['text', 'text', 'text', 'text', 'text', 'real', 'text']
Sample row: ['Footscray', '14.15 (99)', 'South Melbourne', '14.9 (93)', 'Western Oval', 15003.0, '17 April 1971']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Venue" = 'Western Oval';