user: Question: What is the running time of the transmission on BBC Four channels on 23 March 2008?
Columns: ['Date', 'Time', 'Channel', 'Running Time', 'Notes']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['19 March 2008', '21:00', 'BBC Four', '66 min 44 sec', 'Original release']
SQL:

assistant: SELECT "Running Time" FROM "Table" WHERE "Channel" = 'BBC Four' AND "Date" = '23 March 2008';