What is the IATA code of the airport that has a Total Cargo of 1,838,894 Metric Tonnes?
CREATE TABLE "2004_final_statistics" (
  "rank" real,
  "airport" text,
  "location" text,
  "code_iata" text,
  "total_cargo_metric_tonnes" text,
  "2003_rank" text,
  "pct_change" text
);
SELECT "code_iata" FROM "2004_final_statistics" WHERE "total_cargo_metric_tonnes"='1,838,894';