To differentiate it from the orange-fleshed variety, which is what is known as a sweet potato in English-speaking countries, we specify that the white-fleshed Dominican variety of sweet potato is called 'oriental sweet potato' or 'Japanese yam'. Informally it is fine to refer to it as just 'sweet potato.'
So, batata/boniato/camote (with orange flesh) is sweet potato, and the batata with white flesh is oriental sweet potato or Japanese yam. I've also seen 'white sweet potato.' They both have the same scientific name, Ipomoea batatas.