CREATE TABLE table_45637 ("Leader" CLOB, "Party" CLOB, "Leader's Seat" CLOB, "Number of Seats" FLOAT, "Leader since" CLOB)

Which leader has been a leader since 2007?
SELECT "Leader" FROM table_45637 WHERE "Leader since" = '2007'
SELECT "Leader" FROM "table_45637" WHERE "Leader since" = '2007'