Translation:My uncle and aunt live in the village.
How is Duolingo supposed to understand that you do know which is which? It doesn't know the difference between you confusing them and knowing but just changing the order.
Yes though, perhaps not in Indian English (I don't know), but at least in British English 'aunt' first is the more natural order. (Just to say for those Hindi speakers using this to learn English.)
I think this is a case where it just unfortunately doesn't help to try to think about it in terms of English words - because there isn't a parallel for 'a' or 'the' articles.
I think about it as 'do I want to emphasise singularity' - so not 'in English do I say 'a'', but 'in English might I stress 'a''.
E.g. 'villages suck'; 'hey buddy my aunt and uncle live in a village!' - no stress, no एक
E.g. 'maaa, can't we even visit a village', resp. '.. a village' - can be emphasised, एक to replicate that.
(I'm just learning too, so maybe I'll find a case where that doesn't work, but seems to have worked so far in terms of answering Duolingo or understanding something correctly.)