CREATE TABLE table_name_8 (callsign VARCHAR, area_served VARCHAR, frequency VARCHAR)

What is the Callsign with an Area of tamworth and frequency of 0 88.9?
SELECT callsign FROM table_name_8 WHERE area_served = "tamworth" AND frequency = "0 88.9"
SELECT "callsign" FROM "table_name_8" WHERE "0 88.9" = "frequency" AND "area_served" = "tamworth"