1. who has filed the petition ?
2. whose impotency was proven during trial ? husband's / wife's ??
now coming to null & void.
sec. 11 deals with null and void.
the marriage covered by this section is NO marriage AT ALL - since from the inception. the marriage is void eventhough no decree is passed by any court. (M.M.Malhotra vs union of india - SC, Yamunabai anantrao adhav - SC)
sec. 12 deals with annulment.
the marriage covered by this section is valid for all the purposes until ANNULLED by a competent court.
sec. 12 deals with annulment of a valid marriage whereas sec. 11 merely deals with declaration as to nullity.
as far as the rights are concerned, answer of Question no. 2 above & facts-merits of case will be decisive factors. (mostly in favor of the wife)