user: Question: what is the callsign for Independent affiliation?
Columns: ['Media market name', 'Callsign', 'Analog', 'Digital', 'Affiliation']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['American Cable Channel 75 Million Homes', 'WGN America', 'Varies', 'NA', 'Independent']
SQL:

assistant: SELECT "Callsign" FROM "Table" WHERE "Affiliation" = 'Independent';