CREATE TABLE table_204_349 (id DECIMAL, "year" DECIMAL, "conservative\ councillors" DECIMAL, "labour\ councillors" DECIMAL, "independent\ councillors" DECIMAL, "liberal\ councillors" DECIMAL)

why years have no liberal councillors serving ?
SELECT "year" FROM table_204_349 WHERE "liberal\ncouncillors" = 0
SELECT "year" FROM "table_204_349" WHERE "liberal\ncouncillors" = 0