Correct: He led the parade. Incorrect: He lead the parade. Budding writers are increasingly using lead instead of led as the past tense of the verb to lead.
There are three reasons for this confusion. First, the past tense of read, the other common
-ead verb, is read. Second, the word lead, when it's a noun denoting a metal, is pronounced led, just like the past tense of the verb to lead. And third, they don't drill spelling in schools the way they used to.