What is the Diameter (km) of the Valle with a Longitude of 152.5e named before 1997?
CREATE TABLE "valles" (
  "name" text,
  "latitude" text,
  "longitude" text,
  "diameter_km" real,
  "year_named" real
);
SELECT MAX("diameter_km") FROM "valles" WHERE "longitude"='152.5e' AND "year_named"<1997;