<Table> <Tr> <Th_colspan="2"> Sideshow Bob </Th> </Tr> <Tr> <Td_colspan="2"> The Simpsons character </Td> </Tr> <Tr> <Td_colspan="2"> </Td> </Tr> <Tr> <Th_colspan="2"> Information </Th> </Tr> <Tr> <Th> Voiced by </Th> <Td> Kelsey Grammer </Td> </Tr> <Tr> <Th> Gender </Th> <Td> Male </Td> </Tr> <Tr> <Th> Occupation </Th> <Td> Television personality Criminal mastermind Former Mayor of Springfield Former Mayor of Salsiccia scientist professor actor </Td> </Tr> <Tr> <Th> Relatives </Th> <Td> Father: Dr. Robert Terwilliger Sr . Mother: Dame Judith Underdunk Brother: Cecil Terwilliger Wife: Francesca Son: Gino Ex-wife: Selma Bouvier </Td> </Tr> <Tr> <Th_colspan="2"> First appearance </Th> </Tr> <Tr> <Th> The Simpsons </Th> <Td> "The Telltale Head" (1990) </Td> </Tr> </Table> <Tr> <Th_colspan="2"> Sideshow Bob </Th> </Tr>

When did sideshow bob first appear in the simpsons