Olaf Scholz , born in OsnabrÃ 1\/4 ck , is a German politician of the Social Democratic Party of Germany and has been Mayor of Hamburg since 7 March 2011 . Olaf Scholz ( ; born in OsnabrÃ 1\/4 ck ) is a German politician of the Social Democratic Party of Germany an Mayor of Hamburg since 7 March 2011 .