Which German singer has represented Germany two years in a row at the Eurovision Song Contest?

Explanation

The German singer Lena Meyer-Landrut or just "Lena" was born in 1991 in Hannover. In early 2010 she was one of 4500 people casted for the talent show "Unser Star für Oslo", but she made it all the way to the final where the song "Satellite" by John Gordon and Julie Frost was chosen for her. The viewers then voted her through to Oslo, where she won the Eurovision Song Contest in style. The year after she tried to defend her title - as the third winner ever, and the first in 50 years. Her song "Taken by a Stranger" only placed 10th, however.