CREATE TABLE table_203_270 (id DECIMAL, "year" DECIMAL, "competition" TEXT, "venue" TEXT, "position" TEXT, "event" TEXT, "notes" TEXT)

prior to helsinki marathon what previous race did the runner place first ?
SELECT "competition" FROM table_203_270 WHERE "position" = 1 AND id < (SELECT id FROM table_203_270 WHERE "competition" = 'helsinki marathon') ORDER BY id DESC LIMIT 1
SELECT "competition" FROM "table_203_270" WHERE "id" < (SELECT "id" FROM "table_203_270" WHERE "competition" = 'helsinki marathon') AND "position" = 1 ORDER BY "id" DESC NULLS LAST LIMIT 1