CREATE TABLE table_71454 ("Call sign" CLOB, "Frequency MHz" FLOAT, "City of license" CLOB, "ERP W" FLOAT, "Class" CLOB, "FCC info" CLOB)

what is the class of the station with erp w more than 30?
SELECT "Class" FROM table_71454 WHERE "ERP W" > '30'
SELECT "Class" FROM "table_71454" WHERE "ERP W" > '30'