Steering device? Twice left in a row (6)
I believe the answer is:
tiller
'steering device?' is the definition.
(I've seen this before)
'twice left in a row' is the wordplay.
'twice' shows that letters should be duplicated.
'left' becomes 'l' (common abbreviation).
'in' indicates putting letters inside.
'a row' becomes 'tier' (tier is a kind of row**).
'l' doubled is 'll'.
'll' inserted inside 'tier' is 'TILLER'.
(Other definitions for tiller that I've seen before include "Bar that turns rudder in small boat" , "It moves a rudder" , "Lever moving boat's rudder" , "Steering lever" , "Lever to move a boat's rudder" .)