CREATE TABLE table_13913 ("Year ( s ) " CLOB, "Selection show" CLOB, "Venue" CLOB, "National final main host" CLOB, "National final co host" CLOB, "Semi final/heat host" CLOB)

What was the host for the semi final heat, when Terry Wogan was the National Final main host, and Gaby Roslin was the National Final co-host?
SELECT "Semi final/heat host" FROM table_13913 WHERE "National final main host" = 'terry wogan' AND "National final co host" = 'gaby roslin'
SELECT "Semi final/heat host" FROM "table_13913" WHERE "National final co host" = 'gaby roslin' AND "National final main host" = 'terry wogan'