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_21 ( frequency_mhz INTEGER, city_of_license VARCHAR, erp_w VARCHAR )

### Question ###
In Los Banos, California, when the ERP W is than 10, what is the average Frequency MHz?

### Accurate SQL ###

SELECT AVG(frequency_mhz) FROM table_name_21 WHERE city_of_license = "los banos, california" AND erp_w < 10