Members first elected to the State Legislature on or after the passage of Proposition 28 in November of 2012 may serve 12 years in either the Assembly or Senate, or a combined length of service in both the Assembly and Senate, so long as the combined terms do not exceed 12 years of service. Members elected to the State Legislature prior to the passage of Proposition 28 may serve a maximum of three two-year terms in the Assembly and two four-year terms in the Senate as established by the passage of Proposition 140, in November of 1990. Such a legislature, composed of two houses, is called 'bicameral,' while a legislature with only one house is known as 'unicameral.' California employs the bicameral system.