user: Question: How many million viewers watched episode number 20?
Columns: ['Episode No.', 'Series No.', 'Title', 'Directed by', 'Written by', 'Viewers (millions)', 'Original airdate']
Types: ['real', 'real', 'text', 'text', 'text', 'text', 'text']
Sample row: [16.0, 1.0, '"The Apple Doesn\'t Fall"', 'Ben Bolt', 'Richard Stoneman', '8.10', '24September2007']
SQL:

assistant: SELECT "Viewers (millions)" FROM "Table" WHERE "Episode No." = 20.0;