Section 1250 gain

While the facts are not real clear:

• It's not clear if the gain you are referring to is a result of the partnership liquidating and there was gain on the K-1 line 9a, or
• If the gain you are referring to is the result of you selling your partnership interest to a third party and the LT gain is selling price exceeding your tax basis.
• While I'm assuming it is related to bullet #2, you could in fact have some Section 1250 gain.  In order to determine this you would need help from the preparer of the partnership tax return.  This is not always provided even upon asking the question.  The partnership is not real keen on spending $$ to help you determine the tax implications on your personal investment side.  Additionally, this is not a simple computation or estimate.  If this is the case, I would pass as the tax arbitrage between the two tax rates is most likely not that significant.
• If it is related to bullet #1, then I agree with @Anonymous_ that this would have been provided on the K-1 line 9c.

see this link from the iRS

https://www.irs.gov/pub/fatca/int_practice_units/sale_of_partnership_interest.pdf#:~:text=Like%20for%20IRC%20751%20assets%2C%20the%20selling%20partners,tax%20rate%20than%20the%20capital%20gain%20tax%20rate.