CREATE TABLE table_35118 ("Call sign" CLOB, "Frequency MHz" FLOAT, "City of license" CLOB, "ERP W" FLOAT, "Class" CLOB, "FCC info" CLOB)

What is the frequency MHz of the ERP W's greater than 250?
SELECT AVG("Frequency MHz") FROM table_35118 WHERE "ERP W" > '250'
SELECT AVG("Frequency MHz") FROM "table_35118" WHERE "ERP W" > '250'