user: Question: On what date did Dick Johnson with at Calder?
Columns: ['Race Title', 'Circuit', 'City / State', 'Date', 'Winner', 'Team']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Calder', 'Calder Park Raceway', 'Melbourne , Victoria', '8 - 10 Apr', 'Dick Johnson', 'Shell Ultra-Hi Racing']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Winner" = 'Dick Johnson' AND "Race Title" = 'Calder';