The tiny Ontario tourist town of Niagara-on-the-Lake is known for three things: a marmalade mogul, a War of 1812 battle, and a theater festival. We can argue all day about whether Greaves’ citrusy spread is worth the fuss or whether Canada or the U.S. won the war. But when it comes to theater, we have reached a binational agreement: The Shaw Festival is one of the best repertory theaters in North America. So by all means, let’s import its production of My Fair Lady, which was the talk of Ontario in 2011. Molly Smith, Arena Stage’s artistic director, directed the original production and helms the Washington remount. It’s a toast to Professor Higgins, hopefully with jam.