Sub AAAAA()
Dim c As Range
    For Each c In Range("L1:L" & Cells(Rows.Count, "H").End(xlUp).Row)
        If c.Value = 1 Then
            Range(Cells(c.End(xlUp).Offset(1, -11).Row, 1), Cells(c.End(xlDown).Offset(-1).Row, 12)).ClearContents
        End If
    Next c
End Sub