What is the oldest year that the Royal Philharmonic Orchestra released a record with Decca Records?
CREATE TABLE "recordings" (
  "cellist" text,
  "orchestra" text,
  "conductor" text,
  "record_company" text,
  "year_of_recording" real,
  "format" text
);
SELECT MIN("year_of_recording") FROM "recordings" WHERE "orchestra"='royal philharmonic orchestra' AND "record_company"='decca records';