1. दीया (dīyā): This is the most common and widely used spelling. It is pronounced with a long "ee" sound.
2. दिया (diyā): This is a less common spelling, but still valid. It is pronounced with a short "i" sound.
Both spellings are correct, but the first one is more popular.
The choice between the two spellings can depend on the context and the dialect of Hindi being used.