user: Question: What is the callsign where the ICAO is AAR?
Columns: ['AIRLINE', 'ICAO', 'IATA', 'CALLSIGN', 'COMMENCED OPERATIONS']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Air Busan', 'ABL', 'BX', 'AIR BUSAN', '2008']
SQL:

assistant: SELECT "CALLSIGN" FROM "Table" WHERE "ICAO" = 'AAR';