user: Question: Who was the network who had Ken Squier as a host and 13.9 million viewers?
Columns: ['Year', 'Network', 'Lap-by-lap', 'Color commentator(s)', 'Pit reporters', 'Host', 'Ratings', 'Viewers']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1979.0, 'CBS', 'Ken Squier', 'David Hobbs', 'Ned Jarrett Brock Yates', 'Ken Squier', '10.5/29', '15.1 million']
SQL:

assistant: SELECT "Network" FROM "Table" WHERE "Host" = 'Ken Squier' AND "Viewers" = '13.9 million';