CREATE TABLE table_204_54 (id DECIMAL, "pondicherry assembly" TEXT, "duration" TEXT, "name of m.l.a." TEXT, "party affiliation" TEXT, "election year" DECIMAL)

is the current pondicherry assembly the tenth or the twelfth ?
SELECT "pondicherry assembly" FROM table_204_54 ORDER BY "duration" DESC LIMIT 1
SELECT "pondicherry assembly" FROM "table_204_54" ORDER BY "duration" DESC NULLS LAST LIMIT 1