user: Question: What date did the episode with a weekly ranking of 14 air?
Columns: ['Episode No.', 'Airdate', 'Total Viewers', 'Share', 'BBC One Weekly Ranking']
Types: ['real', 'text', 'real', 'text', 'real']
Sample row: [1.0, '2 September 2011', 6114000.0, '24.2%', 9.0]
SQL:

assistant: SELECT "Airdate" FROM "Table" WHERE "BBC One Weekly Ranking" = 14.0;