CREATE TABLE table_77225 ("Call sign" CLOB, "Frequency MHz" FLOAT, "City of license" CLOB, "ERP W" FLOAT, "Class" CLOB, "FCC info" CLOB)

What is Call Sign, when ERP W is greater than 50?
SELECT "Call sign" FROM table_77225 WHERE "ERP W" > '50'
SELECT "Call sign" FROM "table_77225" WHERE "ERP W" > '50'