Table: radio_stations_20
Columns: call_sign
frequency_mhz
city_of_license
erp_w
class
fcc_info

Question: What city of license is associated with call sign w244bk?
SQL: SELECT "city_of_license" FROM radio_stations_20 WHERE "call_sign" = 'w244bk'

Question: What city of license has a Frequency under 107.7, and a call sign of w247aq?
SQL: SELECT "city_of_license" FROM radio_stations_20 WHERE "frequency_mhz" < 107.7 AND "call_sign" = 'w247aq'