Leon Panetta has resigned from the board of directors of Woodland Hills-based Zenith National Insurance Corp. Panetta, who has served on the board since 2000, has been appointed director of the Central Intelligence Agency. His replacement is Jerome L. Coben, who recently retired as partner in the Los Angeles office of Skadden, Arps, Slate, Meagher & Flom LLP. Coben will also fill Panetta’s shoes on the board’s audit and healthcare committees. Zenith also announced it will be paying a quarterly cash dividend of $0.50 per share on May 14. In its year-end earnings report released Jan. 29, Zenith revealed a sharp downturn in its financial fortunes, with net income plunging 60 percent, to $95.3 million versus $233.9 million in 2007.