in the duty station of the circuit judge making the election as of the day before the effective date of this Act. (b) Vacancies For each appointment made under subsection (a) for the twelfth circuit, an equal number of corresponding vacancies in the position of circuit judge for the twelfth circuit shall not be filled. 9. Seniority of judges (a) In general The seniority of each judge— (1) who elects to be assigned to the twelfth circuit under section 6(a)(2)