user: ### NOW ANSWER:
Question: When 24:31 is the run time how many measurements of viewers (in millions) are there?
Columns: ['Episode', 'Broadcast date', 'Run time', 'Viewers (in millions)', 'Archive']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['" Episode One "', '30January1971', '24:39', '6.1', 'Manual colourisation']
SQL:

assistant: SELECT COUNT("Viewers (in millions)") FROM "Table" WHERE "Run time" = '24:31';