Joe Biden and Kamala Harris campaign in Delaware

The presumed Democratic presidential ticket will campaign for the first time Wednesday in Delaware.

Joe Biden has chosen California Senator Kamala Harris as his running mate.

55-year-old Harris was elected to the Senate in 2016, after serving as California’s Attorney General.

It’s the first time in American history a Black woman will be on a major party’s presidential ticket.

U.S. President Donald Trump says he’s “a little surprised” that Biden selected Harris as his running mate.

Trump told reporters at a White House briefing that Harris “was very disrespectful to Joe Biden” during the Democratic primaries.

He’s also noted that Harris “did very poorly” when she ran for the Democratic nomination.

CNN’s Arlette Saenz reports.