Noa is a character of the day who appeared in episode 13.

Noa works as a waitress at a restaurant in Hau'oli City and was the previous winner of the Pokémon Pancake Race. She met Ash and Professor Kukui in her restaurant, where she explained Ash the race's rules. Later, she and her Alolan Raichu were seen training for the race together with Ash and Pikachu.

The next day, Noa and Raichu entered the Pokémon Pancake Race. During the final section of the race, Raichu ran in first place, but due to a distraction caused by Team Rocket and Bewear, Samson Oak's Komala was able to take the lead and win the competition, causing Noa to end up in second place shared with Ash. Although she lost, Noa was content as she had a fun time and told Raichu they would try again next year.

(Source: Bulbapedia, edited)