"How long did the shortest sitting go for (if there was one)?"

Thanks for your question! Each sitting day the members of House of Representatives or senators meet to conduct business in their respective chamber. These meetings or sittings usually run continuously for seven to eleven hours.

Sometimes sittings are short. There are lots of reasons this may be the case. For example, on 24 October 2002 the Senate sat for two minutes! The reason this sitting was adjourned was so Senators could attend a memorial service for the victims of the terrorist attacks in Bali.  

diagram to help explain How long did the shortest sitting go for (if there was one)?