user: Question: What affiliation has an owned since larger than 1991, and also has a channel (tv/rf) of 42?
Columns: ['City of license /Market', 'Station', 'Channel ( TV / RF )', 'Owned Since', 'Affiliation']
Types: ['text', 'text', 'text', 'real', 'text']
Sample row: ['Phoenix', 'KNXV-TV', '15 (15)', 1985.0, 'ABC']
SQL:

assistant: SELECT "Affiliation" FROM "Table" WHERE "Owned Since" > 1991.0 AND "Channel ( TV / RF )" = '42';