The names of these plush dolls are Sydney and Mariah. But if I recall correctly they were originally named Sasha and Malia. It was obvious that they were supposed to be Obama's daughters, but the Obama family complained that they hadn't given their permission to use their names so the dolls names were changed. But it is still obvious that's who they are supposed to be, and even the title of the product at Toywiz is listed as:
Ty Girlz Set of Both Obama Girls Plush Dolls Sweet Sydney & Marvelous Mariah
So if you didn't know before, you saw the name of the product listing, you now know who Sydney and Mariah are supposed to be.

The set costs $12.99 at Toywiz.

Link: http://www.toywiz.com/tyobamagirlz.html