CREATE TABLE table_12547903_2 (callsign VARCHAR2, location__transmitter_site_ VARCHAR2)

What is the callsign of tuguegarao
SELECT callsign FROM table_12547903_2 WHERE location__transmitter_site_ = "Tuguegarao"
SELECT "callsign" FROM "table_12547903_2" WHERE "Tuguegarao" = "location__transmitter_site_"