Sasuke is the current one, because he can use Indra's powers, which is the Perfect Susano'o. Indra's uses a different looking and stronger version of Perfect Susano'o, but that doesn't matter because it still shows that Sasuke's powers are based on Indra's.
Madara was the previous reincarnation of Indra. Now that he has been revived, he has become the reincarnation again. Madara still has all the power he had from being Indra's reincarnation, including PS. There are now two reincarnations of Indra.