For purposes of a formation proceeding, the county board where the petition is filed shall have original and, except as provided by ORS 199.410 (Policy) to 199.519 (Effective date of boundary change), exclusive jurisdiction, coextensive with the boundaries of the proposed district, without regard to county lines. For all purposes under ORS 198.705 (Definitions for ORS 198.705 to 198.955) to 198.955 (Disposition of assets), the jurisdiction of the county board of the principal county shall continue from the time a district is formed until the district is dissolved. [1971 c.727 §6]