DES MOINES — Democratic gubernatorial candidate Fred Hubbell led Iowa’s economic development department for just a short time while the state was cleaning up after a scandal over tax credits for movie projects.But even so, Hubbell was important to the process and provided valuable leadership at the time, according to Iowa Attorney General Tom Miller, also a Democrat.The significance of Hubbell’s contribution to the film credit cleanup was called into question earlier this month during a debate between the Democratic candidates for Iowa governor on Iowa Public Television.Hubbell, a Des Moines businessman, throughout his campaign has touted his work in 2009 as interim director of the state’s economic development board at a time when the film credit scandal rocked the state.