What is the class for the ERP W of 500?
CREATE TABLE "broadcast_translators_of_kjjj" (
  "call_sign" text,
  "frequency_m_hz" real,
  "city_of_license" text,
  "erp_w" real,
  "class" text,
  "fcc_info" text
);
SELECT "class" FROM "broadcast_translators_of_kjjj" WHERE "erp_w"=500;