user: Question: What is the original air date of the episode directed by Paul Marcus?
Columns: ['#', 'Episode', 'Writer', 'Director', 'Original air date', 'Viewing figure']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [11.0, '"Episode 1"(75-minute Christmas special)', 'Bill Gallagher', 'Alan Grint', '21December2008', '6.58 million']
SQL:

assistant: SELECT "Original air date" FROM "Table" WHERE "Director" = 'Paul Marcus';