Who narrated when the vessel operator is de beers?
CREATE TABLE "table1_26168687_3" (
  "no_in_series" real,
  "no_in_season" real,
  "title" text,
  "vessel_type" text,
  "vessel_operator" text,
  "narrated_by" text,
  "original_air_date" real
);
SELECT "narrated_by" FROM "table1_26168687_3" WHERE "vessel_operator"='De Beers';