While spelling mistakes are generally not ideal, one misspelling in the Columbia supplement is unlikely to have a significant negative impact on your application. Admissions officers understand that applicants are human and make occasional errors. They consider a variety of factors when evaluating applications, including academic achievement, extracurricular activities, personal statements, and letters of recommendation. One minor spelling error is not likely to overshadow your overall qualifications.
However, it's still a good idea to carefully proofread your application materials before submitting them to ensure that you present yourself in the best possible light.