CREATE TABLE table_204_503 (id DECIMAL, "year" DECIMAL, "competition" TEXT, "venue" TEXT, "position" TEXT, "notes" TEXT)

the european championships and the 2000 olympic games both involved this competitor in what type of competition ?
SELECT "notes" FROM table_204_503 WHERE "competition" = 'european championships'
SELECT "notes" FROM "table_204_503" WHERE "competition" = 'european championships'