DoTa, because it is a significant improvement over its predecessor, fixing many bugs, balances and incorporating a ton of new features and heroes. Yet as white horn said they are the same thing.
Ekoi, you can use DotA as good as Defense of the Ancents for both RoC and TFT maps, mainly because it means the same, simplier: DotA is a shortcut of Defense of the Ancients.
Obvious that DotA (The dota of the Frozen Throne) is much better, because has much morethings than the old dota, items to combine, a lot of heroes, much more balanced, the streak sounds,... You may don't like DotA, but, you doesn't have how to compare the DOtA of the ROC with the DotA of the FT!