WILMINGTON, Del. - President-elect Joe Biden is set to introduce former presidential rival Pete Buttigieg on Wednesday as his nominee for transportation secretary, adding a youthful voice to an incoming administration so far dominated by people with decades of Washington experience.The 38-year-old former mayor of South Bend, Indiana, would also be the first openly gay person confirmed by the Senate to a Cabinet post.In a tweet on Tuesday, Biden described Buttigieg, who has served as a Navy reserve intelligence officer in Afghanistan, as “a leader, patriot, and problem-solver.”The nomination was applauded by union leaders, transportation industry officials, LGBTQ activists and Democratic lawmakers as a solid pick by Biden.Former Mayor of.