What is the height if de is the position?
CREATE TABLE "table1_20871703_1" (
  "round" real,
  "choice" real,
  "player_name" text,
  "position" text,
  "height" text,
  "weight" real,
  "college" text
);
SELECT COUNT("height") FROM "table1_20871703_1" WHERE "position"='DE';