Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_8 (callsign VARCHAR, area_served VARCHAR, frequency VARCHAR)

### Question ###
What is the Callsign with an Area of tamworth and frequency of 0 88.9?

### Accurate SQL ###

SELECT callsign FROM table_name_8 WHERE area_served = "tamworth" AND frequency = "0 88.9"