user: Question: What was the original air date (atv) of episode 1?
Columns: ['Episode no.', 'Title', 'Director', 'Writer(s)', 'Original Air Date (ATV)', 'Production no.']
Types: ['real', 'text', 'text', 'text', 'text', 'real']
Sample row: [1.0, '" A Case for the Bishop "', 'Alan Perry', 'Gerry and Sylvia Anderson', '21 September 1969', 1.0]
SQL:

assistant: SELECT "Original Air Date (ATV)" FROM "Table" WHERE "Episode no." = 1.0;