CREATE TABLE table_name_13 (frequency_mhz INT, city_of_license VARCHAR)

What is average frequency MHZ when is in portales, new mexico?
SELECT AVG(frequency_mhz) FROM table_name_13 WHERE city_of_license = "portales, new mexico"
SELECT AVG("frequency_mhz") FROM "table_name_13" WHERE "city_of_license" = "portales, new mexico"