user: Question: List the number of bbc rankings with cable rankings of 6.
Columns: ['Episode no.', 'Airdate', 'Viewers', 'BBC Three weekly ranking', 'Cable rank']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1.0, '25 April 2013', '979,000', '2', '9']
SQL:

assistant: SELECT COUNT("BBC Three weekly ranking") FROM "Table" WHERE "Cable rank" = '6';