<Li> Jump up ^ Melton has been cast to take over the role of Reggie from Ross Butler in season 2 . </Li> <Li> Jump up ^ Daniel Yang portrayed Dilton in the pilot . </Li> <Table> <Tr> <Th_colspan="2"> Season </Th> <Th_colspan="2"> Episodes </Th> <Th_colspan="2"> Originally aired </Th> <Th_colspan="2"> Nielsen ratings </Th> </Tr> <Tr> <Th> First aired </Th> <Th> Last aired </Th> <Th> Rank </Th> <Th> Average viewers (in millions inc . DVR) </Th> </Tr> <Tr> <Td> </Td> <Td_colspan="1"> </Td> <Td_colspan="2"> 13 </Td> <Td_colspan="1"> January 26, 2017 (2017 - 01 - 26) </Td> <Td> May 11, 2017 (2017 - 05 - 11) </Td> <Td> 154 </Td> <Td> 1.69 </Td> </Tr> <Tr> <Td> </Td> <Td_colspan="1"> </Td> <Td_colspan="2"> 22 </Td> <Td_colspan="1"> October 11, 2017 (2017 - 10 - 11) </Td> <Td> TBA </Td> <Td> TBA </Td> <Td> TBA </Td> </Tr> </Table> <Tr> <Th_colspan="2"> Season </Th> <Th_colspan="2"> Episodes </Th> <Th_colspan="2"> Originally aired </Th> <Th_colspan="2"> Nielsen ratings </Th> </Tr>

How many episodes does riverdale season one have