I have read an article saying that the Asuras are historically referring to the people of Assyria and so Devas may also be refer to some kind of people historically. What are your thoughts about this. If my case is true, then to whom does Devas may refer to?
Yes, Asur and Deva were historical figures. RigVeda described both. Asur belonged to an earlier age whose genesis is not dealt with in detail. But the genesis of Deva is more than explicit. The real problem lies in the interpretation of RigVeda and understanding the real historical themes it contains. In recent times many scholars have started to treat RigVeda as historical document in order to describe history of ancient India often refer a historical event - "the battle of ten kings" (ref. RV.7.18 (1-25). But they have to go a long way to shade away the connotations held by later scripture about RigVeda which are often contradictory to RigVedic dictum. Not only Assyria, but entire old world namely Sumer, Mesopotamia, Canaan, Persia, Greek and even Egpt seem to be inter-related and influenced by a comman single source and our RigVeda stands to be closure of that. But we have to reveal RigVeda in proper manner discarding the notion later scripture forces upon us that they are the only way to go up to RigVeda for we can not understand 'Asura' properly if we approach RigVeda with it's meaning as 'Rakshas'. To add your information, there is was a great city ' Asur' in ancient Mesopotamia.