Complex sentence: Due to the Lisbon Treaty coming into force Austria currently holds 19 seats in the European Parliament, but with Croatia joining the Union in 2013 it will now locate 18 seats to the Parliament.
Split into simpler sentences: Due to the Lisbon Treaty coming into force, Austria currently holds 19 seats in the European Parliament. But with Croatia joining the Union in 2013 it will now locate 18 seats to the Parliament.