user: Question: What was the series# with the original airdate of October 23, 1967?
Columns: ['Series #', 'Season #', 'Title', 'Director', 'Writer(s)', 'Original Airdate']
Types: ['real', 'real', 'text', 'text', 'text', 'text']
Sample row: [90.0, 1.0, '"The Summit-Five Affair"', 'Sutton Roley', 'Robert E. Thompson', 'September 11, 1967']
SQL:

assistant: SELECT "Series #" FROM "Table" WHERE "Original Airdate" = 'October 23, 1967';