<Tr> <Th> Companion </Th> <Th> Actor </Th> <Th> Seasons </Th> <Th> First serial </Th> <Th> Last serial </Th> </Tr> <Tr> <Td> Polly </Td> <Td> Anneke Wills </Td> <Td> </Td> <Td> The Power of the Daleks </Td> <Td> The Faceless Ones </Td> </Tr> <Tr> <Td> Ben Jackson </Td> <Td> Michael Craze </Td> <Td> </Td> <Td> The Power of the Daleks </Td> <Td> The Faceless Ones </Td> </Tr> <Tr> <Td> Jamie McCrimmon </Td> <Td> Frazer Hines Hamish Wilson </Td> <Td> 4--6, 22 </Td> <Td> The Highlanders </Td> <Td> The Two Doctors </Td> </Tr>

Who is the longest serving doctor who companion