For the set $A={1,2,3}$, define a relation $R$ on the set $A$ as follows:

We have,

$R=\{(1,1),(2,2),(3,3),(1,3)\}$

As, $(a, a) \in R$, for all values of $a \in A$

So, R is a reflexive relation

R can be a symmetric and transitive relation only when element (3, 1) is added

Hence, the ordered pairs to be added to R to make the smallest equivalence relation is (3, 1).