user: Question: What is the airdate when the director is George Spenton-Foster
Columns: ['Episode', 'Title', 'Story', 'Adapted by', 'Director', 'Airdate', 'Exists?']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [101.0, '“No Place Like Earth”', 'John Wyndham', 'Stanley Miller', 'Peter Potter', '4 October 1965', 'Yes']
SQL:

assistant: SELECT "Airdate" FROM "Table" WHERE "Director" = 'George Spenton-Foster';