What is the earliest year borussia dortmund was west and bfc viktoria 1889 was Berlin?
CREATE TABLE "champions_of_pre_bundesliga_oberligen" (
  "year" real,
  "nord" text,
  "west" text,
  "s_dwest" text,
  "berlin" text
);
SELECT MIN("year") FROM "champions_of_pre_bundesliga_oberligen" WHERE "west"='borussia dortmund' AND "berlin"='bfc viktoria 1889';