Columbia allows additional info such as a ds or why columbia essay. Taken from their faqs:
Can I submit an addendum or additional written materials along with my application?
A: Yes. The Admissions Committee believes that candidates should be able to expand upon aspects of their candidacy that are otherwise not represented in the required materials. Some examples include diversity statements, statements of strong interest in Columbia, explanations of undergraduate and/or LSAT performance, etc. We strongly suggest that applicants use their best judgment, in terms of content and length, when considering the submission of supplemental materials.