user: Question: Which Doctor Who episode has a Original airdate (UK) of DVD only?
Columns: ['Episode #', 'Original airdate (UK)', 'Episode title', 'Doctor Who episode', 'Webcast link']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['S1', '26 March 2005', '"A New Dimension"', 'Preview', 'N/A']
SQL:

assistant: SELECT "Doctor Who episode" FROM "Table" WHERE "Original airdate (UK)" = 'DVD only';