CREATE TABLE table_13998897_1 (frequency_mhz VARCHAR, city_of_license VARCHAR)

what's the frequency mhz with city of license being chattanooga, tennessee
SELECT frequency_mhz FROM table_13998897_1 WHERE city_of_license = "Chattanooga, Tennessee"
SELECT "frequency_mhz" FROM "table_13998897_1" WHERE "Chattanooga, Tennessee" = "city_of_license"