user: Question: When is  Cadott Rock Fest taken place?
Columns: ['Date', 'City', 'Country', 'Venue', 'Attendance']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['July 20, 2007', 'Sault Ste. Marie, Michigan', 'United States', 'Kewadin Casino', '10,000']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Venue" = 'Cadott Rock Fest';