To Simple English Users[change source]
Corrected spelling of past tense of "lead" to "led"[change source]
Passive voice is constructed with auxiliary verb and past participle. See https://medium.com/@lucillemoncrief/passive-voice-and-present-participle-a4370c8d87fc
Note example: "The night is ridden by pale horses." "Ridden" is past participle of "ride".
Similarly, "is led by" is a present tense passive construction, so past participle of "lead" should be used.