What is the Nord in 1952, when tennis borussia berlin was Berlin?
CREATE TABLE "champions_of_pre_bundesliga_oberligen" (
  "year" real,
  "nord" text,
  "west" text,
  "s_dwest" text,
  "berlin" text
);
SELECT "nord" FROM "champions_of_pre_bundesliga_oberligen" WHERE "berlin"='tennis borussia berlin' AND "year"=1952;