CREATE TABLE table_203_426 (id DECIMAL, "year" DECIMAL, "title" TEXT, "peak chart positions\ aus" DECIMAL, "peak chart positions\ nz" DECIMAL, "peak chart positions\ uk" DECIMAL, "album" TEXT)

what was the last single to be on the nz charts ?
SELECT "title" FROM table_203_426 WHERE NOT "peak chart positions\nnz" IS NULL ORDER BY "year" DESC LIMIT 1
SELECT "title" FROM "table_203_426" WHERE NOT "peak chart positions\nnz" IS NULL ORDER BY "year" DESC NULLS LAST LIMIT 1