Simplify the following text for a Grade 11 native English-speaking person.
Original: The Social Democratic Party of Germany ( Sozialdemokratische Partei Deutschlands , SPD ) is Germany 's oldest political party , established in 1875 , in the German Parliament .
Simplified: The Social Democratic Party of Germany ( German Sozialdemokratische Partei Deutschlands or SPD ) is the oldest political party of Germany that still exists .