Which ERP W is the lowest one that has a Call sign of w233be?
CREATE TABLE "translators" (
  "call_sign" text,
  "frequency_m_hz" real,
  "city_of_license" text,
  "erp_w" real,
  "class" text,
  "fcc_info" text
);
SELECT MIN("erp_w") FROM "translators" WHERE "call_sign"='w233be';