user: Question: What is the minimum stations owned since KERO-TV?
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 MIN("Owned Since") FROM "Table" WHERE "Station" = 'KERO-TV';