CREATE TABLE table_204_163 (id NUMBER, "airline" CLOB, "icao" CLOB, "iata" CLOB, "callsign" CLOB, "commenced\ operations" NUMBER)

how long between the operations first commenced and the last airline to commence operations ?
SELECT (SELECT "commenced\noperations" FROM table_204_163 ORDER BY "commenced\noperations" DESC LIMIT 1) - (SELECT "commenced\noperations" FROM table_204_163 ORDER BY "commenced\noperations" LIMIT 1)
SELECT (SELECT "commenced\noperations" FROM "table_204_163" ORDER BY "commenced\noperations" DESC FETCH FIRST 1 ROWS ONLY) - (SELECT "commenced\noperations" FROM "table_204_163" ORDER BY "commenced\noperations" FETCH FIRST 1 ROWS ONLY)