CREATE TABLE table_49143 ("Res." TEXT, "Record" TEXT, "Opponent" TEXT, "Method" TEXT, "Event" TEXT, "Round" FLOAT, "Time" TEXT, "Location" TEXT)

The tko (doctor stoppage) method was used in a loss against which opponent?
SELECT "Opponent" FROM table_49143 WHERE "Method" = 'tko (doctor stoppage)' AND "Res." = 'loss'
SELECT "Opponent" FROM "table_49143" WHERE "Method" = 'tko (doctor stoppage)' AND "Res." = 'loss'