user: Question: What is the main date when the round is Third Round Qualifying?
Columns: ['Round', 'Main date', 'Number of fixtures', 'Clubs', 'New entries this round', 'Prize money', 'Player of the Round']
Types: ['text', 'text', 'real', 'text', 'text', 'text', 'text']
Sample row: ['Extra Preliminary Round', '14 August 2010', 201.0, '759 → 558', '402: 358th–759th', '£750', 'n/a']
SQL:

assistant: SELECT "Main date" FROM "Table" WHERE "Round" = 'Third Round Qualifying';