user: Question: What was the original air date for the episode with 3.90 u.s. viewers (millions)?
Columns: ['No.', 'Title', 'Directed by', 'Written by', 'Bens location', 'Original air date', 'U.S. viewers (million)']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, '"Milfay"', 'Rodrigo García', 'Daniel Knauf', 'Milfay, Oklahoma', 'September14,2003', '5.3']
SQL:

assistant: SELECT "Original air date" FROM "Table" WHERE "U.S. viewers (million)" = '3.90';