user: Question: What is the airing date for Costume comedy that has 20 episodes?
Columns: ['Airing date', 'English title (Chinese title)', 'Number of episodes', 'Genre', 'Official website']
Types: ['text', 'text', 'real', 'text', 'text']
Sample row: ['20 Nov 2006- 5 Jan 2007', 'Dicey Business 賭場風雲', 35.0, 'Modern drama', 'Official website']
SQL:

assistant: SELECT "Airing date" FROM "Table" WHERE "Number of episodes" = 20.0 AND "Genre" = 'Costume comedy';