Simplify the following text for a Grade 11 native English-speaking person.
Original: After a career in foreign exchange Key entered the New Zealand House of Representatives in 2002 representing the Auckland constituency of Helensville , a seat that he has held since then .
Simplified: John Key entered the New Zealand Parliament in 2002 representing the north-west Auckland area of Helensville as a National MP , a seat that he still holds .