Section 419B.803 - Jurisdiction(1) A juvenile court having subject matter jurisdiction has jurisdiction over: (a) A party, who has been served in the matter as provided in ORS 419B.812 to 419B.839 to the extent that prosecution of the action is not inconsistent with the Constitution of this state and the Constitution of the United States;(b) A child under 12 years of age who is the subject of a petition filed pursuant to ORS 419B.100; and(c) Any other party specified in ORS 419B.875(1).(2) Juvenile court jurisdiction is subject to ORS 109.701 to 109.834.