As Mabel Bagshawe said there are missing 1861 censues. Those on the FindMyPast do not include the area Tredgar Rd was in, however, those are only the ones known (as the description says).
So looking at Trdegar Rd, there would appear to be missing houses.
The houses go 50-54 on schedule 66-70 p. 11 f 70, followed by 54-59 schedules 71-77 on what would be page 12.
Not sure if the enumerator has made a mistake then because the next page in the sequence is page 19 but numbered folio 71, for houses numbered 87-92, schedules 118-127.
So it would appear that pages 13 -18 are missing for house numbers 60-86. Number 59 was to let and the next entry is no. 87, which should obviously start on a non-existant previous page, since it's for Llewellyn Lloyd aged 5 born Rhymney, down as a son. However although there would appear to pages missing, the folio numbers look to be sequentially correct 70-71.
Edward Watkins born Penderin Breconshire, Catherine born Llangatwg Glamorgan, and Gwenllian aged 14 born Bedwellty, are at Tredegar Rd in 1851
ED, institution, or vessel 23
Piece 2448
Folio 396
Page number 19
Household schedule number 71
