CREATE TABLE table_204_178 (id DECIMAL, "number" TEXT, "south/west end" TEXT, "north/east end" TEXT, "formed" TEXT, "eliminated" TEXT)

which route was eliminated first ?
SELECT "number" FROM table_204_178 ORDER BY "eliminated" LIMIT 1
SELECT "number" FROM "table_204_178" ORDER BY "eliminated" NULLS FIRST LIMIT 1