On what date was the I Dessau Autobahnspinne race?
CREATE TABLE "east_german_championship" (
  "race_name" text,
  "circuit" text,
  "date" text,
  "winning_driver" text,
  "constructor" text,
  "report" text
);
SELECT "date" FROM "east_german_championship" WHERE "race_name"='i dessau autobahnspinne';