CREATE TABLE table_75353 ("Call sign" TEXT, "Frequency MHz" FLOAT, "City of license" TEXT, "ERP W" FLOAT, "Class" TEXT, "FCC info" TEXT)

What is the class of the translator with 10 ERP W and a call sign of w273bl?
SELECT "Class" FROM table_75353 WHERE "ERP W" = '10' AND "Call sign" = 'w273bl'
SELECT "Class" FROM "table_75353" WHERE "Call sign" = 'w273bl' AND "ERP W" = '10'