Simplify the following text for a Grade 9 native English-speaking person.
Original: In December 2006 , Jonathan was selected as running mate to Umaru Yar ` Adua for the ruling PDP presidential ticket in the April 2007 election .
Simplified: In December 2006 , Jonathan was chosen as running mate to Umaru Yar ` Adua for the PDP presidential ticket in the April 2007 election .