CREATE TABLE table_204_710 (id NUMBER, "model" CLOB, "origin" CLOB, "type" CLOB, "versions" CLOB, "in service" CLOB, "notes" CLOB)

what type of aircraft has the longest listed service record ?
SELECT "type" FROM table_204_710 ORDER BY "in service" DESC LIMIT 1
SELECT "type" FROM "table_204_710" ORDER BY "in service" DESC FETCH FIRST 1 ROWS ONLY