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

how many times did she participate in the heptathalon ?
SELECT COUNT(*) FROM table_204_503 WHERE "notes" = 'heptathlon'
SELECT COUNT(*) FROM "table_204_503" WHERE "notes" = 'heptathlon'