If an element, X, can form an oxide that has the formula X2O3, then element X that would most likely be located on the Periodic Table in the group as?

Since oxygen as - 2 charge, and there are three of it in the compound, this makes a total of a - 6 charge. So you will need a positive cation that when you double its charge, you get a + 6 charge. The cation would then have to have a + 3 charge and those are found in group 3