user: Question: When did the episode that had 5.09 million total viewers (both Live and SD types) first air?
Columns: ['Episode number Production number', 'Title', 'Original airdate', 'Rating/Share in Households', '18–49 Rating Live+SD / Live+7', 'Share', 'Live+SD Total viewers', 'Live+7 Day DVR Total viewers']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['1 1-01', 'Pilot', 'September 23, 2009', '5.6/10', '3.0 / 3.4', '8', '8.53 million', '9.63 million']
SQL:

assistant: SELECT "Original airdate" FROM "Table" WHERE "Live+SD Total viewers" = '5.09 million';