Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_30171 ( "Round" text, "Main date" text, "Number of fixtures" real, "Clubs" text, "New entries this round" text, "Prize money" text, "Player of the Round" text )

### Question ###
What is the main date when the round is third round qualifying?

### Accurate SQL ###

SELECT "Main date" FROM table_30171 WHERE "Round" = 'Third Round Qualifying'