According to the Rashba in his Chidushim 118b s. v. 'Mitlonenim', the term 'Ve'Adato' refers to the members of Korach's household. Taken verbatim, these household members would be Levi'im, since Korach was a Levy.
How could that be? The Gemara here is trying to determine who got apportioned the land portions destined to Korach's entourage. Except for the specified cities, individual Levi'im did not get land portions in Eretz Yisrael?!
Mordechai Schwimmer, Brooklyn, USA
But according to the Rashbam (whose words the Rashba is explaining), the Gemara is not making any reference to the actual "Adas Korach" at all, but only to the Mislonenim of Adas Korach (i.e. the 250 non-Levi'im that were with him). That is, the words "Mislonenim ve'Adas Korach" are edited to read "Mislonenim sheb 'Adas Korach", and the Beraisa is saying that the portions of those 250 were divided among the other Israelites. This is clear from the words of Rashbam 117b DH Mislonenim, and this is his intention when he says on 118b DH Elu that the words "b'Adas Korach" in the Pasuk are "the end of the phrase," (i.e. the Pasuk is referring to 'ha'No'adim... b'Adas Korach ,' as opposed to any other No'adim).
The Rashba's point is this: If the 250 were the No'adim of Adas Korach, who were the Adas Korach itself (that did not necessarily lose their portion)? His answer is that Korach and his household (the sons who repented?) were the Adas Korach itself.