CREATE TABLE table_204_284 (id NUMBER, "jurisdiction" CLOB, "adherents" NUMBER, "bishops" NUMBER, "priests" NUMBER, "monastics" NUMBER, "monasteries" NUMBER, "parishes" NUMBER)

how many bishops per adherent in serbia ?
SELECT "bishops" / "adherents" FROM table_204_284 WHERE "jurisdiction" = 'serbia'
SELECT "bishops" / NULLIF("adherents", 0) FROM "table_204_284" WHERE "jurisdiction" = 'serbia'