user: Question: On what date was Richmond hosted as 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: ['Footscray', '14.7 (91)', 'St Kilda', '9.11 (65)', 'Western Oval', 18655.0, '15 July 1972']
SQL:

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