Each of the 51 Members of the Legislative Assembly in the House of Assembly is elected by single member plurality in an electoral district or riding. General elections must be called by the lieutenant governor on the advice of the premier, or may be triggered by the government losing a confidence vote in the House.[11] There are three dominant political parties in Nova Scotia: the Liberal Party, the New Democratic Party, and the Progressive Conservative Party. The other two registered parties are the Green Party of Nova Scotia and the Atlantica Party, neither of which has a seat in the House of Assembly.