user: Question: what are all the date for gtc winners Graeme Mundy Jamie Smyth and gt3 winners Hector Lester Tim Mullen
Columns: ['Round', 'Circuit', 'Date', 'Length', 'Pole Position', 'GT3 Winner', 'GTC Winner']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'Oulton Park', '7 April', '60 mins', 'No. 1 Barwell Motorsport', 'No. 23 Christians in Motorsport', 'No. 81 Team Tiger']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "GTC Winner" = 'Graeme Mundy Jamie Smyth' AND "GT3 Winner" = 'Hector Lester Tim Mullen';