If you have a duplicated entry for the same 1099-DIV, you need to delete one of the entries.
I am assuming you are using TurboTax Desktop (from a disc or download) because the online offering doesn't display a list of ordinary dividends.
See the image below. You can simply click the word Delete to the right of one of the entries to get rid of it.

If this is not the problem, you are asking about, please respond back to this thread with more details.
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