[Solved]Which method is better when sorting a table?

So I am taking a computer science class on khan academy and am working on the algorithm part of the course. The most recent assignment was to sort a table and because I don't know java script well enough to program in it, I decided to write the code in Lua. Now I did not realize that khan academy wanted me to sort the table using a swap function I had created earlier. Here it is:

local testTable = {1, 2, 3}

local function swap(tbl, indexOne, indexTwo)
	
	local secondIndexThingy = tbl[indexTwo]
	
	tbl[indexTwo] = tbl[indexOne]
	tbl[indexOne] = secondIndexThingy
	
end

swap(testTable, 1, 3)

So I went ahead and wrote this without the swap:

local numList = {3, 6, 4, 7, 9, 2, 5, 1, 8, 6}

local function sortTableFromMinToMax(tbl)
	
	local sortedTable = {}

	for i = 1, #tbl do
		
		local smallestNumSoFar = false
		local indexOfSmallNum
	
		for index,v in pairs(tbl) do
			
			wait()
			
			if smallestNumSoFar then
				if v < smallestNumSoFar then
					
					smallestNumSoFar = v
					indexOfSmallNum = index
					
				end
				
			else
				
				smallestNumSoFar = v
				indexOfSmallNum = index
			
			end	
		end
		
		table.insert(sortedTable, smallestNumSoFar)
		table.remove(tbl, indexOfSmallNum)
		
	end
	
	return sortedTable
	
end

and it works. But I wanted to know. Is it better to do it the way khan academy had me doing it? Or is returning a whole new table rather than manipulating the old one more efficient?