Democrat Gabrielle Giffords was seriously wounded in a mass shooting in January 2011 and resigned her congressional seat in January 2012 .
Democrat Gabrielle Giffords had represented the 8th district since 2007 .
Democrat Gabrielle Giffords , who had represented the 8th district since 2007 , was seriously wounded in a mass shooting in January 2011 and resigned her congressional seat in January 2012 .