Riddle one: who came second, with second first? (5)
I believe the answer is:
sieve
'riddle one' is the definition.
'sieve' can be an answer for 'riddle' (I've seen this before). I am not certain of the 'one' bit.
'came second with second first?' is the wordplay.
'came second' becomes 'eve' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'with' means one lot of letters go next to another.
'second' becomes 's' (common abbreviation).
'first?' becomes 'i' (Roman numeral for one or first).
's'+'i'='si'
'eve' put after 'si' is 'SIEVE'.
'who' acts as a link.
Can you help me to learn more?
(Other definitions for sieve that I've seen before include "Fine strainer" , "Kitchen strainer" , "Utensil with meshed bottom" , "Jumblies' vessel" , "used by the Jumblies" .)